Incandescent lamp base lock



Feb. 19, 1935.

F. E. CARL INCANDESCENT LAMP BASE LOCK Filed May 19, 1934 Invenlor F'ec/ F Vera-7Z 8T7 Patented Feb. 19, 1935 INCANDE SCENT LAMP BASE LooK Fred Everett Carl, Los Angeles, Calif.

Application May 19, 1934, Serial No. 726,565

2 Claims.

This invention relates to a lock for the base of incandescent lamps or bulbs, the general object of the invention being to provide means whereby a bulb cannot be removed from the socket after it has been once placed therein so as to prevent theft of the bulb.

This invention also consists in certain other features of construction and in the combination and arrangement of the several parts, tobe hereinafter fully described, illustrated in the accompanying drawing and specifically pointed out in the appended claims. In describing the invention in detail; reference will be had to the accompanying drawing wherein like characters denote like or. corresponding parts throughout the several .views, and in which:- 7 V Figure 1 is an elevation of the base part of a bulb, showing the invention applied thereto.

Figure 2 is a fragmentary section on line 2-2 of Figure 1.

Figure 3 is an elevation of the base, with the locking member removed.

Figure 4 is a section on line 4-4 of Figure 1.

As shown in these views, a portion of the threaded part 5 of the base 1 of the bulb 2 is formed with a recess 3 in a part of its circumference, the recess gradually increasing in depth from one end to the other, the deep end forming a shoulder 4 and the other end gradually merging into the regular threaded part of the base, as shown more clearly in Figure 4.

A plate 6, grooved as shown and tapering from one end to its other, is adapted to fit in the recess and the ribs formed by the grooves in the plate are formed with small projections '7. This plate forms a. detachable wedge shaped screw-threaded liner. As will be seen from Figure 4, this liner or plate substantially fills the recess so that the base of the bulb can be screwed in its socket in the ordinary manner, but when an attempt is made to unscrew the bulb from the socket, the

projections 7 will engage parts of the internal wall of the socket, which will cause the liner or plate to remain practically stationary as the base is turned, so that the liner or plate will move partly out of the recess and thus wedge the base of the bulb in the socket and prevent any further turning movement of the base.

Thus

it will be impossible to remove the bulb from the socket.

When the bulb is broken, the base can be bent inwardly by a suitable tool so as to permit the base to be removed from the socket and in order to indicate where the tool should be placed, I provide a projection 8 on theouter end of the base which extends over a part of the bulb and is not covered by the socket when the base is screwed into the socket. As will be seen, this projection will indicate the position of the locking plate.

It is thought from the foregoing description that the advantages and novel features of the invention will be readily apparent.

It is to be understood that changes may be made in the construction and in the combination and arrangement of the several parts, provided that. such changes fall within the scope of the appended claims.

of its threads.

FRED EVERE'I'I CARL. 

